Device for the spraying of shoe soles onto shoe shafts

ABSTRACT

The improved device disclosed herein is used for the spraying of shoe soles onto shoe shafts. The shoe shafts are drawn over a last that is carried by a movable last slide and are emplaceable upon the sealing edge of molding jaws, which sealing edge bounds a hollow space corresponding to the dimensions of the shoe sole to be formed. The emplacement operation continues until a preselected pressure has been reached between the shoe contour of the shoe shaft nd the sealing edge of the molding jaws. When this preselected pressure is reached, an arresting device is actuated to hold the last slide, and thus the last and shoe shaft, against further movement while the soles are formed on the shoe shafts.

United States Patent Niklaz [54] DEVICE FOR THE SPRAYING OF SHOE SOLESONTO SHOE SHAFTS [72] Inventor: Manfred Niklarz, Rinteln, Germany [73]Assignee: Stubbe Maschinenfabrik G.m.b.l-l., Vlotho, Germany [22] Filed:Oct. 8, 1970 [21] Appl. No.: 79,006

30 CM, 18/30 CS, 42 l-l,43,17 S. 17 C. 65; 91/24. 27, 28;425/135,l50,119,125, 214

[56] References Cited UNITED STATES PATENTS 3,522,632 8/1970 Wessel..18/42 H 51 Sept. 19, 1972 Primary Examiner-J. Spencer OverholserAssistant Examiner-David S. Safran AttorneyMolinare, Allegretti, Newitt& Witcofi [5 7] ABSTRACT The improved device disclosed herein is usedfor the spraying of shoe soles onto shoe shafts. The shoe shafts aredrawn over a last that is carried by a movable last slide and areemplaceable upon the sealing edge of molding jaws, which sealing edgebounds a hollow space corresponding to the dimensions of the shoe soleto be formed. The emplacement operation continues until a preselectedpressure has been reached between the shoe contour of the shoe shaft ndthe sealing edge of the molding jaws. When this preselected pressure isreached, an arresting device is actuated to hold the last slide, andthus the last and shoe shaft, against further movement while the solesare fonned on the shoe shafts.

6 Claims, 3 Drawing Figures Roudier ..269/22 PATENTED 1 9 m2 3 e92 .449

SHEET 3 {1F 3 Fig.3

IN VEN TOR.

46m /mm DEVICE FOR THE SPRAYING OF SHOE SOLES ONTO SHOE SHAFTSBackground Of The Invention The invention relates to an improved devicefor the spraying of shoe soles onto shoe shafts, and more particularly,to a device wherein the shoe shaft drawn over the last is emplaceable,by means of a movable last slide, upon the sealing edge of the moldingjaws, which sealing edge bounds a hollow space corresponding to thedimensions of the shoe sole to be formed.

In automatic soling machines, it is necessary that the shoe shaft drawnover the last is pressed, with an emplacing force, upon the sealing edgeof the molding jaws of an injection molding mold, so as to assure thatthere will not be any expulsion of sprayed material between shoe shaftand the sealing edge of the molding jaws during the spraying operation.Simultaneously, however, it must be assured that the edge pressurebetween contour of the shoe shaft and sealing edge of the molding jawsdoes not, in consequence of the emplacing force, lead to the result thatthe upper portion (the upper leather) of the shoe shaft is damaged oreven destroyed.

In the devices already known, the last, with the drawn-on shoe shaft, ismoved by means of a pneumatic cylinder, hydraulic cylinder or a togglelever against the injecting molding mold until the last is held in thedesired position by adjustable stops. In these known devices, it isnecessary to adjust the stops precisely so that the shoe shaft will beconnected, with full sealing effect, with the injection molding mold,without the upper leather of the shoe shaft being damaged or destroyed.

In the case of shoe sole spray materials with poor flow properties,increased injection pressures have to be used so that the sole isexactly developed, and the increased forces resulting from theseincreased injection pressures attempt to lift or move the last away fromthe mold so as to lead to the expulsion of material from the mold. Ifmaterial is expelled, then an expensive, aftertreatment becomesrequired, which is undersired in any case. In such cases, andparticularly when pneumatic or hydraulic actuating cylinders are used, aforce is caused to act during the soling process on the actuating(operating) device to which the sole is indirectly fastened. This forceis considerably greater than the permissible emplacing force of the lastupon the spray mold, i.e., the force at which a damage to the upperleather does not occur. However, because of the use of stops, this forceis subdivided, namely, (1) as the emplacing force of the last upon theinjection molding mold, and (2) as additional force which is absorbed bythe stops. Through the use of stops, a lifting-off of the last from theinjection molding mold can be avoided.

These prior devices have the disadvantage, however, that the stops haveto be adjusted extremely precisely, whereby valuable working time islost. Further, in these devices, the varying leather thicknesses in aproduction course or run are not taken into account, whereby differentsealing edge pressures occur on the shoe shaft, and it is not alwayspossible to avoid damage to the shoe shaft. Furthermore, an additionaltime-consuming arranging of the stops is required if lasts of differingheight are used. Here again, the adjustment must be precise since itshould be made certain that no material expulsion takes place and,further, any damage to the upper leather should be avoided insofar aspossible.

These problems in connection with the spraying-on of shoe soles on shoeshafts are solved according to the invention wherein a variablyresponding, arresting device is used to fix and hold the last slide inposition when a selectable, precisely defined, edge pressure betweenshaft contour and the sealing edge of the O molding jaws has beenreached during the emplace ment operation.

As a result of the use of the arresting device of the present invention,the use of conventional stops is not required and there is nothing toreset or adjust when shoe lasts of differing leather thicknesses areused in a production series or run. Rather, the sealing between shoeshaft and injecting molding mold takes place entirely independently ofthe most diverse leather thicknesses and the most diverse last heightsand there is always an exactly defined emplacing force between the shoeshaft and the mold, which emplacing force prevents any damaging of theshoe shaft and any material expulsion therebetween. In other words, as aconsequence of the use of the arresting device of the present invention,the above-mentioned stops, as well as the adjusting process associatedwith them, are dispensed with, and this provides an appreciableadvantage over the prior devices. Here, according to the presentinvention, upon reaching the defined emplacement force, with which theshoe shaft is pressed against the injection molding mold, the movementof the last, which is connected with the last slide, is arrested so thatthe force (also called last drive-up force) which builds up in theinjection molding mold in consequence of the spray pressure and tends tolift the shoe shaft from the sealing edges of the injecting molding moldis completely absorbed by the arresting device.

The defined emplacing force, which is selected so as to assure that nodamage takes place to the upper leather of the shoe last and that nomaterial expulsion occurs, is, for example in the case of ahydraulically operated last slide, preselected and adjusted by means ofa variably controllable pressure switch. This defined emplacement forceis selected or set only once, and its choice is completely independentof the differing material thickness of the shoe shafts and is likewiseindependent of the differing heights of the different lasts used. Also,as noted above, the use of the present invention eliminates thecomplicated and time-consuming arranging and setting required of thestops utilized in the hitherto known devices, as a result of theaforementioned fluctuations in the material thickness of the shoe shaftleather or the shoe shaft material and the use of different lastheights.

A preferred embodiment of the arresting device of the present inventionis positioned adjacent to the last slide and consists of a sparconnected with the last slide and of a locally fixed, deformable shellsurrounding this spar. The shell is joinable, in closed linkage, withthe spar by action of pressure on a pressure space surrounding the spar.

DESCRIPTION OF THE DRAWINGS In the following, there is described indetail a preferred embodiment of the present invention with the aid ofthe following drawings wherein:

FIG. 1 shows in schematic representation a device for the spraying ofshoe soles onto shoe shafts with an arresting device and anelectro-hydraulic control device;

FIG. 2 shows a section from FIGURE 1 in enlarged representation; and

FIG. 3 shows a longitudinal section through the ar resting device, inwhich the left half of the drawing shows the arresting device in thereleased state and the right side shows it in the fixed state.

DESCRIPTION OF THE PREFERRED EMBODIMENT The device represented in FIGURE2 for the spraying of shoe soles onto shoe shafts is used, as a rule, asone station of an automatic soling machine, equipped with severalstations. In FIGURE 2, the device, as shown, is set for the rhythmicallyinjecting of plastomers and elastomers into the injection molding mold 1for an injecting, spray assembly.

Before the start of the injection spraying operation, the last 2 withthe lasted-on shoe shaft 3 is emplaced or placed on the injectionmolding mold 1. Thus, in dependence on the emplacement force between thelast 2 and the sealing edge of the mold jaws S, the shoe shaft contour 4is pressed between the last and the edge of the mold jaws 5.

The emplacing of the shoe shaft upon the mold jaws 5 is accomplished bymeans of a hydraulically operated cylinder 6 which has a piston 7slidably positioned therein. The movement of the piston 7 istransferrable through a piston rod 8 extending out of the cylinder 6directly to a last slide 9 carrying the last 2. The last slide 9 ispositioned and arranged such that in the emplacing of the shoe shaft 3drawn over the last 2 upon the sealing edge of the mold jaws 5, there isaccomplished a uniform sealing over the entire circumference of thesealing edge.

In order to increase the production performance of such an automaticsoling machine, it is provided, as a rule, that the last 2 is notfastened directly to the last slide 9, but on a turnable last revolver10, which has two oppositely situated lasts. Through the use of a doublelast, there is achieved a saving of rirne, because during the solingoperation onto the one time, shaft, the finished shoe is de-lasted fromthe oppositely situated last and thereafter another shoe shaft can belasted thereto. For reasons of clarity, the second last fastened to thespanning area 11 of the last revolver is not included in FIGURE 3.

The hydraulic raising and lowering of the last 2 is accomplished by theintroduction of pressurized fluid on the corresponding piston surfacesof piston 7 through the feed lines 12 in the cylinder 6. The upper limitof the stroke movement of the last is adjustable by means of the supportbracket and adjusting screw 13 positioned above the cylinder 6. Thelimiting of the lowering movement of the last 2 is accomplished by theemplacing of the shoe shaft 3 drawn over the last 2 upon the injectionmolding form. An arresting device 14, which consists essentially of aspar l5 permanently connected with the last slide 9 and of a locallyfixed clamping shell 16 surrounding the spar, arrests or restrainsfurther movement of the last. The construction of this arresting deviceis more clearly shown in FIGURE 3 and its manner of functioning is to beexplained in detail below.

As noted above, in FIGURE 3 the arresting device 14 is shown on the leftside of the FIGURE in the released state, while the right side thereofis shown in the arrested state. In the released state of the arrestingdevice 14, the spar 15 is in sliding contact with the clamping shell orsleeve 16. The clamping shell 16 consists of an elastic, thin-walledmaterial, and it is surrounded by a thick-walled cylinder 17, with theshell 16 being sealingl connected with the cylinder adjacent to itsends, so that a closed generally annular pressure space 19 results,which, by means of the opening 20, may be acted upon by a pressurefluidv For the fixing of the last 2 by means of the arresting devices14, pressurized fluid is admitted to the pressure space 19 and thethin-walled shell 16 moves into contact or places itself-as shown on theright side of FIGURE 3-securely around the spar 15, so that, inconsequence of closed linkage between the spar 15 and the shell 16,movement or a lifting off of the last 2 from the sealing edge of themolding jaws 5 is no longer possible. In order to be able to absorb thereaction forces evoked in the arresting device 14, the clamping shell 16has an internal shoulder 21 on the cylinder 17, and an external shoulder22 which by means of a shoulder flange 18, is fastened to the machineframe, not shown, of the automating soling machine.

With the aid of the schematic representation shown in FIGURE 1 therewill now be described in detail the course of functioning of thearresting device 14. The emplacing of the shoe shaft 3 on the moldingjaws, i.e., the lowering of the last slide 9 from its upper restposition, as results when the pressure line 24 is connected with thefeed line 25 for causing the lowering movement of the piston 7.

This is accomplished by means of a multiple-way valve 26. The valve 26is held by springs 27 in a centered or zero position, in which pressureflow is blocked. When one of the two magnets 28 is actuated,

then either the pressure line 24 is connected with the feed line 25 forthe descending movement of the piston 7 or the pressure line 24 isconnected with the feed line 29 for the lifting movement of the piston7, while simultaneously the remaining feed line or the other line fromthe cylinder 6, i.e., the line then functioning as lead-off from thecylinder 6, is connected with the tank or sump 30.

The speed of the lowering and lifting movement of the piston 7 can beinfluenced by adjustable valves 3] and 32 in the lines 25 and 29,respectively. These valves 31 and 32 are constructed as choke, nonreturnvalves, whose constriction is effective, in each case, only inconnection with flow in the direction of the runoff or lead-off from thecylinder 6.

When the pressure line 24 is connected with the feed line 25, then thelast 2 descends. After the emplacing of the shoe shaft 3 upon thesealing edge of the molding jaw 5, the pressure of the fluid in cylinder6 above the piston 7 builds up to a preselected, final value, whichcauses the requisite edge pressure between shoe shaft and injectionmolding mold. The emplacing force resulting from this preselected finalpressure is sensed by a conventional pressure switch 33 which isconnected with the upper end of the cylinder 6, and which on thereaching of this pressure, places a controlling voltage on theconventional relay R. The relay R operates a working contact r whereby,by means of a magnetically operated multiple-way valve 34, the pressureline 24 is connected, by means of the feed line 35, to the pressurespace 19 of the arresting device 14. Thereby the last 2 is arrested orheld in the position wherein the previously exactly defined edgepressure exists between shoe shaft and the sealing edge of the moldingjaws so as to make possible an expulsion-free spraying, (injection) andalso to prevent any damage to the shoe upper leather.

To prevent the pressure above the piston 7 from rising inadmissibly highafter. the arresting device has been activated, and for reasons ofsafety, a conventional adjustable pressure reducing valve 36 isinstalled in the feed line 25 to the cylinder 6.

After completion of the injection process and after the passing of arequired vulcanization or hardening time, the finished footwear islifted by means of the last 2 from the injection molding mold 1. Morespecifically, through the operation of the multiple-way valve 26, thecylinder space above the piston 7 becomes pressureless, i.e., connectedto the tank or sump 30, and simultaneously the feed line 29 is connectedwith the line 24. Immediately after the lowering of the pressure in thecylinder space above the piston 7, the control voltage is taken from therelay R by means of the pressure switch 33, whereby the working contactr falls or opens and the multiple-way valve 34 is brought, by means ofthe spring 37, into its zero position, in which it connects the line 35with the tank or sump 30. Thereby, the arresting device 14 is, thus,released, so that the lifting movement of the last 2 can be initiated.

The foregoing is a description of the preferred embodiment of thepresent invention, and the scope of the invention includes allmodifications, which would be obvious to those skilled in this art, tothe invention as described in the following claims.

I claim:

1. An improved device for the injection of the shoe soles onto shoeshafts adjacent to the contour of the shoe shaft comprising:

last means over which shoe shafts may be drawn;

mold means including molding jaws having a sealing edge which defines ahollow space corresponding to the dimensions of the shoe sole to beformed on the shoe shaft;

last slide means connected to the last means and movable to emplace theshoe shaft drawn over the last means upon the sealing edge of themolding jaws of the molding means; and

arresting means for selectively holding the last slide means againstfurther movement; means for sensing the pressure exerted by the shaftcontour ofthe shoe shaft on the sealing edge of thc molding jaws of themolding means during emplacement of the shoe shaft drawn over the lastmeans upon the sealing edge of the molding jaws of the molding means,the pressure sensing means including means for actuating the last slidearresting means so that the last slide arresting means holds the lastslide means against further movement, when a preselected pressure hasbeen reached between the shaft contour of the shoe shaft and the sealingedge of the molding jaws of the moldingmeans. 2. T e improved device asdescribed in claim 1 wherein the arresting means includes: a sparconnected to and movable with the last slide means and a means forselectively gripping the spar so as to prevent further movement thereof.

3. The improved device as described in claim 2 wherein the grippingmeans includes: a cylinder means surrounding the spar and an elasticmeans disposed between the cylinder means and the spar which mayselectively engage the spar.

4. The improved device as described in claim 3 wherein the elastic meansis an annular elastic member which is connected at its ends with thecylinder means so as to define space between the elastic member and thecylinder means; and wherein the cylinder means includes means forintroducing pressurized fluid into the space between the cylinder meansand the elastic member for causing the elastic member to be expandedagainst the spar.

5. The improved device as described in claim 4 wherein the last slidemeans is moved in a shoe shaft emplacing direction by a hydraulic fluidpiston and cylinder means; wherein the pressure sensing means senses thepressure of the hydraulic fluid acting in the hydraulic fluid piston andcylinder means; wherein the means for introducing pressurized fluid intothe space between the cylinder means and the elastic member is actuatedby the actuating means when the pressure of the fluid acting in thehydraulic piston and cylinder means exceeds a preselected value.

6. The improved device as described in claim 5 wherein when the pressureof the hydraulic fluid acting in the hydraulic piston and cylinder meansfalls below said value, the pressurized fluid in the space between theelastic member and the cylinder means is placed in communication with asump whereby the spar is again free to move with respect to the cylindermeans.

1. An improved device for the injection of the shoe soles onto shoeshafts adjacent to the contour of the shoe shaft comprising: last meansover which shoe shafts may be drawn; mold means including molding jawshaving a sealing edge which defines a hollow space corresponding to thedimensions of the shoe sole to be formed on the shoe shaft; last slidemeans connected to the last means and movable to emplace the shoe shaftdrawn over the last means upon the sealing edge of the molding jaws ofthe molding means; and arresting means for selectively holding the lastslide means against further movement; means for sensing the pressureexerted by the shaft contour of the shoe shaft on the sealing edge ofthe molding jaws of the molding means during emplacement of the shoeshaft drawn over the last means upon the sealing edge of the moldingjaws of the molding means, the pressure sensing means including meansfor actuating the last slide arresting means so that the last slidearresting means holds the last slide means against further movement,when a preselected pressure has been reached between the shaft contourof the shoe shaft and the sealing edge of the molding jaws of themolding means.
 2. The improved device as described in claim 1 whereinthe arresting means includes: a spar connected to and movable with thelast slide means and a means for selectively gripping the spar so as toprevent further movement thereof.
 3. The improved device as described inclaim 2 wherein the gripping means includes: a cylinder meanssurrounding the spar and an elastic means disposed between the cylindermeans and the spar which may selectively engage the spar.
 4. Theimproved device as described in claim 3 wherein the elastic means is anannular elastic member which is connected at its ends with the cylindermeans so as to define space between the elastic member and the cylindermeans; and wherein the cylinder means includes means for introducingpressurized fluid into the space between the cylinder means and theelastic member for causing the elastic member to be expanded against thespar.
 5. The improved device as described in claim 4 wherein the lastslide means is moved in a shoe shaft emplacing direction by a hydraulicfluid piston and cylinder means; wherein the pressure sensing meanssenses the pressure of the hydraulic fluid acting in the hydraulic fluidpiston and cylinder means; wherein the means for introducing pressurizedfluid into the space between the cylinder means and the elastic memberis actuated by the actuating means when the pressure of the fluid actingin the hydraulic piston and cylinder means exceeds a preselected value.6. The improved device as described in claim 5 wherein when the pressureof the hydraulic fluid acting in the hydraulic piston and cylinder meansfalls below said value, the pressurized fluid in the space between theelastic member and the cylinder means is placed in communication with asump whereby the spar is again free to move with respect to the cylindermeans.